Bbmb 316 Exam 3

Front 1

A small molecule will spontaneously cross a membrane if this condition is met

Back 1

the molecule is a steroid hormone.

the molecule is soluble in nonpolar solutions. the molecule is lipophilic.

Front 2

Which of the following is the electron donor used for the reductive biosynthesis of fatty acids?

Back 2

NADPH

Front 3

Which of the following membranes would be the least fluid?

Back 3

a bilayer made of lipids with saturated 18-carbon fatty acids

Front 4

The transport process that requires protein assistance but no energy input

Back 4

facilitated diffusion

Front 5

Consider the Figure shown below, which illustrates the relation between the sodium-glucose symporter and the Na+—K+ ATPase. If the symporter were inhibited, what effect would such inhibition have on the ATPase?

Back 5

inhibition of the symporter would eventually lead to the inhibition of the ATPase.

Front 6

What forces stabilize the lipid bilayer?

Back 6

A) van der Waals interactions

B) electrostatic and hydrogen bonding between the polar heads and surrounding water

C) hydrophobic effect

Front 7

Insulin is a peptide hormone that regulates carbohydrate and fat metabolism in the body. Which of the following statement(s) is(are) correct concerning insulin molecules

Back 7

binds to membrane receptors and transmits information into the cell without crossing the plasma membrane

Front 8

Identify the mechanism by which the stomach maintains a pH of ~ 1-2 pH units

Back 8

H+/K+ ATP-dependent proton pump

Front 9

Digestion is

Back 9

the process of breaking down large molecules in food.

Front 10

What is the scientific name for particles responsible for transport of lipids in the circulatory system?

Back 10

chylomicrons

Front 11

When activated, the insulin receptor results in the mobilization of ____________________ transporters to the cell surface.

Back 11

glucose

Front 12

Which of the following molecules has a higher phosphoryl-transfer potential than ATP?

Back 12

A) phosphoenolpyruvate (PEP)

B) creatine phosphate

C) 1,3-bisphosphoglycerate (1,3-BPG)

Front 13

In a chemically coupled series of reactions A is converted to D in two successive steps. What is the free-energy change (ΔGº') for the overall reaction

Back 13

-13 kJ mol-1 (-3 kcal mol-1)

Front 14

Why does ATP have a high phoshoryl-transfer potential?

Back 14

A. stabilization by hydration

B. charge repulsion, resonance stabilization

Front 15

Identify the molecule that plays a role as an catabolic electron carrier

Back 15

NAD+

Front 16

Which of the following molecules provides the most free energy by its complete oxidation

Back 16

methane

Front 17

In the oxidation of a substrate, the nicotinamide ring of NAD+ accepts a hydrogen ion and two electrons, at the same time (concurrently) that the reducing agent (reductant) releases a hydrogen ion(proton) into the solvent/solution.

Back 17

True

Front 18

What is substrate-level phosphorylation?

Back 18

ATP synthesis when the phosphate donor is a substrate with a higher phosphoryl-transfer potential than ATP

Front 19

The goal(s) of catabolism

Back 19

to capture the energy of carbon oxidation as ATP

Front 20

Identify the molecule(s) that act(s) as a phosphoryl-group carrier with high energy transfer potential

Back 20

ATP

Front 21

Glucose is the most stable hexose because the hydroxyl groups are all

Back 21

in the equatorial position

Front 22

The anaerobic breakdown of glucose to pyruvate is called

Back 22

glycolysis

Front 23

Glycolysis produces a net gain of _________ moles of ATP per 1 mole of glucose

Back 23

2

Front 24

What is the function of a thioester intermediate such as the one formed from glyceraldehyde 3-phosphate (shown below)?

Back 24

The thioester allows the two-step reaction to be coupled so that the second reaction, the energetically unfavorable phosphorylation, can proceed.

Front 25

Which two 3-carbon molecules are generated by the cleavage of fructose-1,6-bisphosphate?

Back 25

glyceraldehyde-3-phosphate and dihydroxyacetone phosphate

Front 26

During excerise, glycolysis is stimulated by the following factor(s):

Back 26

feed-forward stimulation of pyruvate kinase by fructose 1,6-bisphosphate

Front 27

The glycolytic pathway is tightly controlled. Which three enzymes catalyze virtually irreversible reactions and act to regulate glycolysis?

Back 27

hexokinase, phosphofructokinase and pyruvate kinase

Front 28

Although glucose is the major sugar degraded by the glycolytic pathway, other sugars such as galatose and fructose are often present. These sugars:

Back 28

are metabolized by the glycolytic pathway by conversion to intermediates in the pathway.

Front 29

Complete the following sentence: Gluconeogenesis is the synthesis of glucose from

Back 29

carbon skeletons of some amino acids.

glycerol.

pyruvate formed from lactate.

non-carbohydrate precursors.

(all)

Front 30

Complete the following sentence: The graph below depicts the allosteric regulation of

Back 30

phosphofructokinase

Front 31

In the relaxed muscle fiber, glycolysis is inhibited by the following factor(s):

Back 31

negative feedback on hexokinase and high energy charge of the cell

Front 32

The conversion of glucose 6-phosphate to glucose takes place in the ___________________.

Back 32

endoplasmic reticulum

Front 33

An intermediate that is decarboxylated and phosphorylated to produce phosphoenolpyruvate:

Back 33

oxaloacetate

Front 34

In the gluconeogenic pathway, identify the enzyme responsible for catalyzing the reaction below:

Back 34

Fructose 1,6-bisphosphatase

Front 35

The steps in glycolysis that are different than those in gluconeogenesis are catalyzed by these enzymes:

Back 35

pyruvate kinase, phosphofructokinase, hexokinase

Front 36

If a eukaryotic cell was broken open and subcellular organelles were separated from the cytoplasm, in which compartment (organelle) would most citric acid enzymes be found?

Back 36

mitochondria

Front 37

Which co-factor is critical for the decarboxylation catalyzed by the pyruvate dehydrogenase complex?

Back 37

thiamine pyrophosphate (TPP)

Front 38

Which co-factor is critical for the transfer of acetyl groups to CoA by the pyruvate dehydrogenase complex?

Back 38

lipoamide

Front 39

Match the term below with its description: Acetyl CoA

Back 39

Fuel for the citric acid cycle

Front 40

The PDH (pyruvate dehydrogenase) subunit responsible for the regeneration of the oxidized form of lipoamide:

Back 40

Dihydrolipoyl dehydrogenase (E3)